You’ve likely heard of the 100 mile diet: sourcing all your food from farmers within 100 miles of home. But what if you could keep the kids in comestibles from a farm a couple of subway stops away?

In recent years, awareness of the health and environmental benefits of locally-grown food has spiked, with commensurate increase in demand. Meanwhile, the relentless press of humanity continues to chew up Ontario farmland like a swarm of bipedal locusts, replacing crops with fibreboard townhouses and strip mall 7-11s, while the ghost of Tom Malthus nods with grim satisfaction.

To help supply meet demand, there’s a growing interest in urban farming, both here and around the world. Toronto already boasts more than two hundred community gardens which help supply inexpensive, nutritious food to Torontonians, while also teaching old-school skills to those tilling their hobbit-sized fields.

Still, the output of community gardens is necessarily small. Available land is limited, production is labour-intensive, and distribution is logistically challenging. But what if we could figure out urban food production on an industrial scale? What if we had downtown farms that could feed not just a few households, but whole neighbourhoods?

Welcome to the vertical farm.
A few years back Gordon Graff, a University of Waterloo architecture grad student, proposed a towering urban farm for downtown Toronto. The boldness and novelty of the idea grabbed headlines, but the $1.5 billion price tag failed to attract developer interest.

However, high-rise farming is moving forward elsewhere.

Alterrus has begun construction on a 5,700 square foot hydroponic facility atop a parking garage, which will grow leafy green vegetables in a “vertical growing system.” Besides being more efficient space-wise than single-level farms, the company claims their technology produces higher crop yields and uses fewer resources than conventional field agriculture.

On a larger scale, Plantagon, a Swedish company majority-owned by the Onondaga Nation in New York state, has broken ground on their first vertical greenhouse in Linköping, Sweden. Expected to be in production by 2014, the 57 metre (approximately 15 storey) structure (pictured at right) not only grows green, but will use waste CO2 and other outputs from nearby industrial facilities to run the operation.

Plantagon also says that their technology needs only five per cent of the water necessary for crops grown using traditional methods, and being indoors, doesn’t require the use of pesticides.

The Swedish installation is essentially a pilot. Ultimately, Plantagon aspires to building greenhouse skyscrapers that can feed thousands.

But urban industrial farming isn’t all visioneering and pie in the sky. A test farm has been up and running in South Korea since 2011. A larger working vertical farm has been operating since last year in Singapore, and now produces and sells half a ton of vegetables per day.

The idea has its detractors. Skeptics argue the whole idea is unscalable, and that large vertical farms would be insatiable consumers of energy to keep the plants lit, healthy, and harvested—the Plantagon greenhouse will be powered by a diesel generator, surprising for a notionally green installation. They also point to the limited types of crop that can practically be grown in vertical facilities, and to the human labour needed to substitute for machines used on conventional farms.

High rise factory farming may be less bucolic and more Bladerunner than we’d prefer. But with the population of the GTA expected to rise to 9.3 million people by 2036 (and that of the planet to a staggering 9 billion) and urbanization, climate change, and other human folly shrinking existing cropland, Cityplaces full of spinach may be the only thing standing between us and Soylent Green.